Organic materials designed for commercial and industrial use are often transported in equipment having a metal surface. Typical organics include oils, greases, latexes, waxes, paraffins, tars, asphaltenes, and the like, and typical metals which are employed include carbon steel, stainless steel, copper, aluminum, brass, and alloys. Specifically, the organic materials often contaminate the metal surfaces they are contained or transported in such as organic materials transported in rail cars; processing equipment employed in petrochemical plants and refineries; ship tanks; and the like. Typically these objects are cleaned in hot caustic solution to dissolve the organic contaminant. Using such a solution, however, suffers from numerous drawbacks. Caustic is relatively slow to clean a vessel because chemical hydrolysis has to occur. Moreover, the caustic is dangerous to handle for workers since skin contact often results in chemical burns. The caustic can also react with ammonium-based contaminants to release free ammonia which is a hazard and irritant to workers. Caustic solution is not very reusable and must be totally disposed of as a hazardous waste due to contaminants and high pH (&gt;12).
U.S. Pat. No. 5,356,482 to Mehta et al. proposes a process for decontaminating process equipment and vessels. In particular, Mehta et al. proposes utilizing a cleaning agent such as a terpene-based extractant which is vaporized by the use of steam to remove organic contaminants, particularly potentially hazardous contaminants such as benzene. The use of steam, however, is disadvantageous in that it requires additional cost in terms of energy needed to vaporize the water.
It would be desirable to provide a composition and method of decontaminating a surface which utilizes substantially non-hazardous chemicals which are biodegradable, and does not require steam in the contaminant removal process. Moreover, it would be particularly desirable to provide a composition and method for decontaminating a surface such that subsequent to decontamination, the composition may be readily re-used.